http://www.mediafire.com/?ld7xupli4qn1u0d
This is your file link. That copyix.com part is just to spam you.
Center of the mediafire page, there should be a big green button saying "Download (7.93 MB)". Click that. You should then be able to download the .RAR file containing the rom, but first you need to have a program to extract from a .RAR compressed folder, like "jZip" at http://www.jzip.com/. Then open up the .gba file with VBA, move the .sav file to the same foldeer as your .gba file, and you've got game. I think the .ips file there adds some patch to the game, but it only works if you rename the file the EXACT same as the .gba file is named.

Okay. In order to extract the ROM files, you need to have a program that can handle .RARs. So go to http://www.jzip.com/ and download it with the button. (just an example, 7zip and winRAR work too but this one's free). Now you open the Pokemon_Light_Platinum_Full_English.rar file with jZip. You should see some files in it, including VBA and the .gba file. Then you extract the .gba and the .sav to a folder. You can then start up VBA, and open the .gba.

I THINK that's all you need to do to play light platinum, Miles said that the .ips adds a patch to the game, but I have no clue about that. Sorry if this didn't help a lot.